Monopolar recording in a fully implantable medical sensing device for programming guidance

This application claims priority to U.S. Provisional Application No. 63/196,433, filed Jun. 3, 2021, the entire contents of which is hereby incorporated by reference.

The disclosure relates to medical devices, and more specifically, sensing electrical signals from a patient.

Implantable medical devices, such as electrical stimulators or therapeutic agent delivery devices, have been proposed for use in different therapeutic applications, such as deep brain stimulation (DBS), spinal cord stimulation (SCS), pelvic stimulation, gastric stimulation, peripheral nerve stimulation, functional electrical stimulation or delivery of pharmaceutical agents, insulin, pain relieving agents or anti-inflammatory agents to a target tissue site within a patient. In some therapy systems, an implantable electrical stimulator delivers electrical therapy to a target tissue site within a patient with the aid of two or more electrodes, that may be deployed by medical leads and/or on a housing of the electrical stimulator, or both. In some therapy systems, therapy may be delivered via particular combinations of the electrodes carried by leads and/or by the housing of the electrical stimulator.

During a programming session, that may occur during implantation of the medical device, during a trial session, or during an in-clinic or remote follow-up session after the medical device is implanted in the patient, a clinician may generate one or more therapy programs (also referred to as therapy parameter sets) that are found to provide efficacious therapy to the patient, where each therapy program may define values for a set of therapy parameters. A medical device may deliver therapy to a patient according to one or more stored therapy programs. In the case of electrical stimulation, the therapy parameters may define characteristics of the electrical stimulation waveform to be delivered. In examples in that electrical stimulation is delivered in the form of electrical pulses, for example, the therapy parameters may include an electrode configuration including an electrode combination and electrode polarities, an amplitude, that may be a current or voltage amplitude, a pulse width, and a pulse rate.

In general, this disclosure is directed to devices, systems, and methods for utilizing brain signals, such as LFPs (local field potentials), to identify electrodes on one or more implantable leads that may be most appropriate for delivery of stimulation. For example, the system may sense signals between each electrode on a lead using a particular electrode as a reference (e.g., a reference electrode). Such sensing may be referred to as monopolar sensing. In some examples, the reference electrode is an electrode on a different lead than the lead including the sense electrode(s). In some examples, the reference electrode may be a distal most or proximal most electrode on the same lead as the sensing electrodes. In some examples, the system may perform the sensing of signals in this manner on each lead of the system. In this manner, the system may sense signals between different electrodes in order to highlight relevant differences between stimulation delivered via each of the electrodes. The system may then generate information regarding these signals and inform the clinician of these signals. The physician, or the system, may then determine parameters for stimulation including which electrodes to use as stimulation electrodes using these obtained signals (e.g., the LFP distribution) instead of having to test stimulation provided by each electrode combination. The use of LFP guided programming may reduce an amount of time required to program therapy. This may be particularly true when using segmented leads. Additionally, monopolar sensing may be less susceptible to electrocardiogram artifacts than bipolar sensing, resulting in less noisy sensed signals.

As one example, an implantable medical device includes sensing circuitry configured to sense electrical signals from a first plurality of electrode combinations, each of the first plurality of electrode combinations comprising a same reference electrode of a plurality of electrodes and at least one different sense electrode of the plurality of electrodes, the plurality of electrodes being associated with one or more leads; and processing circuitry configured to: record the sensed electrical signals from the first plurality of electrode combinations; and provide representations of the recorded sensed electrical signals.

As another example, a method includes receiving, by processing circuitry, electrical signals from a first plurality of electrode combinations, each of the first plurality of electrode combinations comprising a same reference electrode of a plurality of electrodes and at least one different sense electrode of the plurality of electrodes, the plurality of electrodes being associated with one or more leads; recording, by the processing circuitry, the sensed electrical signals from the first plurality of electrode combinations; and providing, by the processing circuitry, representations of the recorded sensed electrical signals.

As another example, a non-transitory computer-readable storage medium stores instructions that, when executed, cause processing circuitry to: receive electrical signals from a first plurality of electrode combinations, each of the first plurality of electrode combinations comprising a same reference electrode of a first plurality of electrodes of a first lead and at least one different sense electrode of a second plurality of electrodes of a second lead; record the sensed electrical signals from the first plurality of electrode combinations; and provide representations of the recorded sensed electrical signals.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

In general, the disclosure is directed to utilizing sensed electrical signals, such as LFPs within the brain, to identify which electrode or electrodes of a plurality of electrodes on an implantable lead may be appropriate to deliver electrical stimulation. While primarily described herein with respect to a brain, the techniques of this disclosure may be used to identify which electrode or electrodes on an implantable lead may be appropriate to deliver electrical stimulation to other parts of the anatomy, such as the spinal cord, pelvic floor, peripheral nerves, and the like.

Many brain disorders may be associated with abnormal brain function. In one example, Parkinson's Disease (PD) is a progressive neuro-degenerative disorder characterized by the depletion of dopaminergic neurons in the basal ganglia-thalamo-cortical network. As PD progresses, the manifestations of the disease may include one or more of the characteristic motor dysfunctions that include one or more of akinesia, bradykinesia, rigidity, and tremor. In some examples, deep brain stimulation (DBS) therapy may be used to deliver electrical stimulation to treat motor symptoms in medication-refractory PD patients. In some examples, DBS therapy may involve the unilateral or bilateral implantation of one or more leads into the brain to deliver electrical stimulation to target structures in the basal ganglia. Selection of effective stimulation parameters for DB S therapy may be time-consuming for both the clinician (e.g., a physician, nurse, or technician) and the patient. As such, it may be desirable to reduce the amount of time consumed to select stimulation parameters. In addition, the trial-and-error approach for determining appropriate electrode combinations and/or other stimulation parameters may subject the patient to undesirable side effects during this lengthy process and/or may result in less than optimal stimulation parameters, thus lessening the therapeutic value of any therapy delivered.

The target region associated with a disease (e.g., PD) may generate signals of interest (e.g., Beta waves that may be indicative of symptoms such as tremor in PD). As described herein, a system may sense signals between different combinations of electrodes in order to highlight relevant differences between the sensed signals from each of the electrodes. The system may then generate information regarding these signals, such as information that may be presented to a clinician and/or information used by the system to select parameter values for stimulation such as two or more stimulation electrodes. The sensed signals may be between electrodes at different circumferential positions and/or electrodes at different axial positions on one lead and a reference electrode on another lead (e.g., monopolar sensing). The clinician, or the system, may then determine parameters for stimulation based on one or more characteristics of these obtained signals instead of having to test stimulation provided by each electrode combination. For example, parameters for stimulation may include which electrodes are used for stimulation, polarity of the electrodes used for stimulation (e.g., anode or cathode), and parameters of the electrical stimulation signal, such as voltage or current amplitude, frequency, waveform shape, on/off cycling state (e.g., if cycling is “off,” stimulation is always on, and if cycling is “on,” stimulation is cycled on and off) and, in the case of electrical stimulation pulses, current or voltage pulse amplitude, pulse rate, pulse width, and other appropriate parameters such as duration or duty cycle.

For example, a Beta rhythm may be localized with the dorsal subthalamic nucleus (STN). It may be helpful to select stimulation electrodes that may generate an electric field that affects this oscillatory region of the brain, which may in some examples be stimulation electrodes that are positioned proximally or optimally relative to the region. The system may detect electrical signals between different electrode combinations and process the signals to generate spectral power characteristics for one or more frequencies. The system may then identify the electrode combinations, and thus axial (or level) and circumferential positions of the electrode combinations, associated with the spectral power characteristics indicative of stronger Beta waves. In some examples, the system may select the electrode combination associated with stronger Beta waves for targeted stimulation to this region of tissue. In addition, or alternatively, the system may present this information to a clinician to enable the clinician to review the LFPs sensed (and/or characteristics such as spectral power) from different electrode combinations. The clinician may then select an electrode combination associated with the stronger (e.g., larger amplitude spectral power) electrode amplitudes associated with Beta waves for subsequent sensing and/or stimulation therapy.

Each lead may have electrodes disposed at different axial positions along the length of the lead. These electrodes may be ring electrodes and/or segmented electrodes that only reside around a limited portion of the perimeter of the lead. In the case of segmented electrodes that only reside around a limited portion of the perimeter of the lead, at a given axial position, each lead may have electrodes at different circumferential positions (e.g., at different positions around the perimeter of the lead). Hence, two or more segmented electrodes may be positioned at the same axial position along the length of the lead (e.g., on the same level of the lead). As an illustration, a 1-3-3-1 lead would have, in order, a ring electrode at a first, most proximal axial level, three segmented electrodes at different circumferential positions of a second, more distal axial level, three segmented electrodes at different circumferential positions of a third, still more distal axial level, and a ring electrode at a fourth, most distal axial level. In some examples, the system may group electrodes together as one polarity, e.g., as a group of cathodes, for use with another electrode of another polarity, e.g., an anode, or vice versa. The system may perform such groupings in order to balance impedance between cathodes and anodes and improve sensing fidelity. In one example, to sense between an axial level of the lead with a ring electrode and another axial level with multiple smaller, segmented electrodes at different circumferential positions, the system may group together those electrodes at different circumferential positions to create a virtual ring electrode (also referred to herein as segmented electrodes in a ring mode) that may improve sensing between an actual ring electrode and the virtual ring electrode. The grouping together of those electrodes at different circumferential positions to create a virtual ring electrode may be referred to as a ring mode.

Sensing electrical signals between different electrodes, including electrodes at different axial positions and at different circumferential positions, may provide valuable information about where certain electrical signals (e.g., signals in the Beta frequency band or Beta waves, alpha waves, gamma waves, theta waves, and high frequency oscillations (HFO)) are originating from within tissue. In this manner, the system (or a clinician) may use this information to determine which electrodes (and/or other stimulation parameter values) should be used to deliver electrical stimulation therapy. In one example, the system may provide information representative of the sensed electrical signals via a display to enable a clinician to program stimulation more effectively and in less time than using trial-and-error approaches.

As part of generating the one or more therapy programs, a clinician may select which electrodes to use for stimulation. For example, a clinician may utilize the medical device to record sensed electrical signals between different pairs of electrodes on a single lead (e.g., bipolar sensing) and a display to display representations of the recorded bipolar sensed electrical signals. However, generating the one or more therapy programs based on the representations of the recorded bipolar sensed electrical signals may not be intuitive for many clinicians. Additionally, bipolar sensing may be susceptible to electrocardiogram artifacts which may result in noisy sensed electrical signals, further complicating the stimulation electrode selection process.

Alternatively, as part of generating the one or more therapy programs, a clinician may perform a review to test each electrode and the effect of stimulating using each electrode on the symptoms of a patient. However, this process may take as several hours and be uncomfortable for the patient. According to the techniques of this disclosure, a medical device may utilize monopolar sensing to assist a clinician in selecting appropriate electrodes to use for electrical stimulation therapy. The time it may take to complete the monopolar sensing may be as short as three minutes, thereby greatly reducing the time it may take to select the appropriate electrodes for stimulation, reducing the chance of error in selecting the appropriate electrodes, and/or reduce the uncomfortable effects for the patient. The techniques of this disclosure include using monopolar sensing to sense brain signals (or other signals) and process those signals so as to convert the brain signals into representations of the brain signals and to display the representations of the brain signals.

is a conceptual diagram illustrating an example therapy systemthat is configured to deliver therapy to patientto manage a disorder of patient. Patientordinarily will be a human patient. In some cases, however, therapy systemmay be applied to other mammalian or non-mammalian non-human patients. In the example shown in, therapy systemincludes medical device programmer, implantable medical device (IMD), lead extension, and one or more leadsA andB (collectively “leads”) with respective sets of electrodes,. IMDincludes a stimulation generator (not shown in) configured to generate and deliver electrical stimulation therapy to the STN region of brainof patientvia electrodesand/orof leadsA andB, respectively.

In the example shown in, therapy systemmay be referred to as a deep brain stimulation (DBS) system because IMDis configured to deliver electrical stimulation therapy directly to the STN within brain. DBS may be used to treat or manage various patient conditions, such as, but not limited to, seizure disorders (e.g., epilepsy), pain, migraine headaches, psychiatric disorders (e.g., major depressive disorder (MDD), bipolar disorder, anxiety disorders, post-traumatic stress disorder, dysthymic disorder, and obsessive compulsive disorder (OCD)), behavior disorders, mood disorders, memory disorders, mentation disorders, movement disorders (e.g., essential tremor or Parkinson's disease), Huntington's disease, Alzheimer's disease, or other neurological or psychiatric disorders and impairment of patient.

In the example shown in, IMDmay be implanted within a subcutaneous pocket in the pectoral region of patient. In other examples, 1 MBmay be implanted within other regions of patient, such as a subcutaneous pocket in the abdomen or buttocks of patientor proximate the cranium of patient. Implanted lead extensionis coupled to circuitry in 1 MBvia proximal electrical contacts that connect to electrical terminals in connector block(also referred to as a header). Lead extensionmay include, for example, distal electrical contacts that electrically couple to proximal electrical contacts of leadsA,B, which in turn may be coupled to respective electrodes,via conductors within leadsA,B. The proximal electrical contacts of leadsA,B and the distal electrical contacts of lead extensionelectrically couple the electrodes,carried by leadsto the proximal contacts of lead extensionvia conductors within the lead extension, and in turn to circuitry of IMDvia terminals in connector block. Lead extensiontraverses from the implant site of IMBwithin a chest cavity of patient, along the neck of patientand through the cranium of patientto access brain. IMDmay be constructed of a biocompatible material that resists corrosion and degradation from bodily fluids. IMDmay comprise a hermetically sealed housingto substantially enclose components, such as a processor, a therapy module, and memory.

In the example shown in, leadsare implanted within the right and left hemispheres, respectively, of brainin order to deliver electrical stimulation to one or more regions of brain, that may be selected based on many factors, such as the type of patient condition that therapy systemis implemented to manage. Other implant sites for leadsand IMBare contemplated. For example, IMDmay be implanted on or within craniumor leadsmay be implanted within the same hemisphere at multiple target tissue sites or IMBmay be coupled to a single lead that is implanted in one or both hemispheres of brain.

Leadsmay be positioned to deliver electrical stimulation to one or more target tissue sites within brainto manage patient symptoms associated with a disorder of patient. Leadsmay be implanted to position electrodes,at desired locations of brainvia any suitable technique, such as through respective burr holes in the skull of patientor through a common burr hole in the cranium. Leadsmay be placed at any location within brainsuch that electrodes,are capable of providing electrical stimulation to target therapy delivery sites within brainduring treatment. In the case of Parkinson's disease, for example, leadsmay be implanted to deliver electrical stimulation to regions within the STN, either unilaterally or bilaterally. Target therapy delivery sites not located in brainof patientare also contemplated.

Although leadsare shown inas being coupled to a common lead extension, in other examples, leadsmay be coupled to IMDvia separate lead extensions or directly coupled to IMD. Moreover, althoughillustrates therapy systemas including two leadsA andB coupled to IMDvia lead extension, in some examples, therapy systemmay include one lead or more than two leads.

In the examples shown in, electrodesA,D,A, andD of leadsare shown as ring electrodes. Ring electrodes may be relatively easy to program and may be capable of delivering an electrical field to any tissue adjacent to leads. ElectrodesB,C,B, andC of leadsmay have different configurations. For example, electrodesB,C,B, andC of leadsmay each have a complex electrode array geometry that is capable of producing shaped electrical fields. An example of a complex electrode array geometry may include an array of segmented electrodes positioned at different axial positions along the length of a lead, as well as at different angular (i.e., circumferential) positions about the periphery, e.g., circumference, of the lead. The complex electrode array geometry may include multiple electrodes (e.g., partial ring or segmented electrodes), such as electrodeB,C,B, andC that each include multiple individually programmable electrodes located at different positions around the perimeter of each respective lead. Although electrodesA,D,A, andD may be ring electrodes that each extend fully around the perimeter of the lead, any of these electrodes may be replaced, in other examples, by multiple electrodes located at different positions around the perimeter of the lead. Although electrodesB,C,B, andC may be include multiple electrodes (e.g., partial ring electrodes or segmented electrodes), any of these electrodes may be replaced by ring electrodes. By using electrodes disposed at different positions around the perimeter of the lead, IMDmay deliver directional stimulation, with electrical stimulation that may be directed in a specific direction from leadsto enhance therapy efficacy and reduce possible adverse side effects from stimulating a large volume of tissue. As a further example, the electrodes may be pad electrodes, that may be carried on a paddle lead or a cylindrical lead.

As illustrated in the example of, the set of electrodesof leadA may include electrodesA,B,C, andD, and the set of electrodesof leadB may include electrodesA,B,C, andD. In some examples, each of electrodesandmay be configured to independently deliver electrical stimulation.

In some examples, outer housingof IMDmay include one or more stimulation and/or sensing electrodes. Some or all of the electrodes may be used for both sensing and stimulation, or some electrodes may be dedicated to sensing while some other electrodes may be dedicated to stimulation. Housingmay comprise an electrically conductive material that is exposed to tissue of patientwhen IMDis implanted in patient, or an electrode may be attached to housing. Hence, in some examples, electrode combinations for stimulation and/or sensing may be formed by combinations of one or more electrodes on a lead or leads and one or more electrodes on housingof IMD, or by combinations of two or more electrodes on a lead or leads. In other examples, leadsmay have shapes other than elongated cylinders as shown inwith active or passive tip configurations. For example, leadsmay be paddle leads, spherical leads, bendable leads, or any other type of shape effective in treating patient.

IMDmay deliver electrical stimulation therapy to brainof patientaccording to one or more stimulation therapy programs (also referred to herein as “set of stimulation parameter values”). A stimulation therapy program may define one or more electrical stimulation parameter values for therapy generated by a stimulation generator (not shown in) of IMDand delivered from IMDto a target therapy delivery site within patientvia one or more electrodes,. The electrical stimulation parameters may define an aspect of the electrical stimulation therapy, and may include, for example, voltage or current amplitude of an electrical stimulation signal, a charge level of an electrical stimulation, a frequency of the electrical stimulation signal, waveform shape, on/off cycling state (e.g., if cycling is “off,” stimulation is always on, and if cycling is “on,” stimulation is cycled on and off) and, in the case of electrical stimulation pulses, current or voltage pulse amplitude, pulse rate, pulse width, and other appropriate parameters such as duration or duty cycle. In addition, if different electrodes are available for delivery of stimulation, an electrode combination may further characterize a therapy parameter of a therapy program, that may define selected electrodes,and their respective polarities. In some examples, stimulation may be delivered using a continuous waveform and the stimulation parameters may define this waveform, although stimulation will generally be described herein as being defined by stimulation pulses.

In addition to being configured to deliver therapy to manage a disorder of patient, therapy systemmay be configured to sense bioelectrical brain signals or another physiological parameter of patient. For example, IMDmay include a sensing circuitry that is configured to sense bioelectrical brain signals within one or more regions of brainvia a subset of electrodes,, another set of electrodes, or both. Accordingly, in some examples, electrodes,may be used to deliver electrical stimulation from the stimulation generator to target sites within brainas well as sense brain signals within brain. However, IMDmay also use a separate set of sensing electrodes to sense the bioelectrical brain signals. In some examples, the sensing circuitry of IMDmay sense bioelectrical brain signals via one or more of the electrodes,that are also used to deliver electrical stimulation to brain. In other examples, one or more of electrodes,may be used to sense bioelectrical brain signals while one or more different electrodes,may be used to deliver electrical stimulation.

Programmeris an external device that is configured to wirelessly communicate with IMBas needed to provide or retrieve therapy information. Programmeris an external computing device that the user, e.g., the clinician and/or patient, may use to communicate with IMB. For example, programmermay be a clinician programmer that the clinician uses to communicate with IMDand program one or more therapy programs for IMD. In addition, or instead, programmermay be a patient programmer that allows patientto select programs and/or view and modify therapy parameter values. The clinician programmer may include more programming features than the patient programmer. In other words, more complex or sensitive tasks may only be allowed by the clinician programmer to prevent an untrained patient from making undesired changes to IMD.

Programmermay be a hand-held computing device with a display viewable by the user and an interface for providing input to programmer(i.e., a user input mechanism). For example, programmermay include a small display screen (e.g., a liquid crystal display (LCD) or a light emitting diode (LED) display) that presents information to the user. In addition, programmermay include a touch screen display, keypad, buttons, a peripheral pointing device, voice activation, or another input mechanism that allows the user to navigate through the user interface of programmerand provide input. If programmerincludes buttons and a keypad, the buttons may be dedicated to performing a certain function, e.g., a power button, the buttons and the keypad may be soft keys that change in function depending upon the section of the user interface currently viewed by the user, or any combination thereof.

In other examples, programmermay be a larger workstation or a separate application within another multi-function device, rather than a dedicated computing device. For example, the multi-function device may be a notebook computer, tablet computer, workstation, one or more servers, cellular phone, personal digital assistant, or another computing device that may run an application that enables the computing device to operate as a secure medical device programmer. A wireless adapter coupled to the computing device may enable secure communication between the computing device and IMB.

When programmeris configured for use by the clinician, programmermay be used to transmit programming information to IMB. Programming information may include, for example, hardware information, such as the type of leads, the arrangement of electrodes,on leads, the position of leadswithin brain, one or more therapy programs defining therapy parameter values, therapeutic windows defining upper and lower amplitude limits for one or more electrodes,, and any other information that may be useful for programming into IMD. Programmermay also be capable of completing functional tests (e.g., measuring the impedance of electrodes,of leads).

The clinician may also generate and store therapy programs within IMDwith the aid of programmer. Programmermay assist the clinician in the creation/identification of therapy programs by providing a system for identifying potentially beneficial therapy parameter values. For example, during a programming session, the physician may select an electrode combination for delivery of therapy to the patient. The physician may have the option to create several therapy programs. Some programs may have the same electrode combination (but different values of at least one other therapy parameter) and these therapy programs may be organized into subsets, each subset having the same electrode combination. The physician may select an efficacious therapy program for each subset based on a displayed list of sensed LFP signals from electrode combinations. The clinician may select a therapy program based on a list displayed on external programmerof combinations of electrodes providing the largest LFP spectral power to provide therapy to patientto address symptoms associated with the patient condition.

Programmermay also be configured for use by patient. When configured as a patient programmer, programmermay have limited functionality (compared to a clinician programmer) in order to prevent patientfrom altering critical functions of IMDor applications that may be detrimental to patient.

Whether programmeris configured for clinician or patient use, programmeris configured to communicate with IMDand, optionally, another computing device, via wireless communication. Programmer, for example, may communicate via wireless communication with IMDusing radio frequency (RF) and/or inductive telemetry techniques that may comprise techniques for proximal, mid-range, or longer-range communication. Programmermay also communicate with another programmer or computing device via a wired or wireless connection using any of a variety of local wireless communication techniques, such as RF communication according to the 802.11 or Bluetooth specification sets, infrared (IR) communication according to the IRDA specification set, or other standard or proprietary telemetry protocols. Programmermay also communicate with other programming or computing devices via exchange of removable media, such as magnetic or optical disks, memory cards, or memory sticks. Further, programmermay communicate with IMDand another programmer via remote telemetry techniques known in the art, communicating via a personal area network (PAN), a local area network (LAN), wide area network (WAN), public switched telephone network (PSTN), or cellular telephone network, for example.

Therapy systemmay be implemented to provide chronic stimulation therapy to patientover the course of several months or years. However, therapy systemmay also be employed on a trial basis to evaluate therapy before committing to full implantation. If implemented temporarily, some components of therapy systemmay not be implanted within patient. For example, patientmay be fitted with an external medical device, such as a trial stimulator, rather than IMD. The external medical device may be coupled to percutaneous leads or to implanted leads via a percutaneous extension. If the trial stimulator indicates therapy systemprovides effective treatment to patient, the clinician may implant a chronic stimulator within patientfor relatively long-term treatment. In another example, a clinician in an operating room may obtain acute recordings during lead placement and before coupling the lead with an IMD. In this example, an external device (e.g., an external electrophysiology system) may couple to the medical lead in order to obtain sensed electrical signals.

While DBS may successfully reduce symptoms of some neurological diseases, the stimulation may also cause unwanted side effects, also referred to herein as adverse effects. Side effects may include incontinence, tingling, loss of balance, paralysis, slurred speech, loss of memory, loss of inhibition, and many other neurological problems. Side effects may be mild to severe. DBS may cause one or more adverse effects by inadvertently providing electrical stimulation pulses to anatomical regions near the targeted anatomical region. These anatomical regions may be referred to as regions associated with adverse stimulation effects. For this reason, a clinician may program IMDwith a therapy program (or a plurality of therapy programs) that defines stimulation parameter values that balance effective therapy and minimize side effects. For example, a clinician may select an electrode(s) to deliver stimulation that did not sense the largest LFP spectral power if the electrode(s) that did sense the largest LFP spectral poser is located in a region associated with adverse stimulation effects or if the largest LFP spectral power is too high for patient comfort.

With the aid of programmeror another computing device, a clinician may select values for therapy parameters for therapy system, including an electrode combination. By selecting particular electrodes of electrodes,and electrode combinations for delivering electrical stimulation therapy to patient, a clinician may modify the electrical stimulation therapy to target one or more particular regions of tissue (e.g., specific anatomical structures) within brainand avoid other regions of tissue within brain. In addition, by selecting values for the other stimulation parameter values that define the electrical stimulation signal, e.g., the amplitude, pulse width, and pulse rate, the clinician may generate an efficacious therapy for patientthat is delivered via the selected electrode subset. Due to physiological diversity, condition differences, and inaccuracies in lead placement, the parameter values may vary between patients.

During a programming session, the clinician may determine one or more therapy programs that may provide effective therapy to patient. Patientmay provide feedback to the clinician as to the efficacy of the specific program being evaluated, that may include information regarding adverse effects of delivery of therapy according to the specific program. In some examples, the patient feedback may be used to determine a clinical rating scale score. Once the clinician has identified one or more programs that may be beneficial to patient, patientmay continue the evaluation process and determine which program best alleviates the condition of patientor otherwise provides efficacious therapy to patient. Programmermay assist the clinician in the creation/identification of therapy programs by providing a methodical system of identifying potentially beneficial therapy parameters.

In another example, leadmay be implanted directly at the target tissue (e.g., in a region with the strongest beta oscillation or largest amplitude of a target frequency). In another example, leadmay be implanted based purely on anatomy alone (e.g., placed in the STN). In either of these examples, due to various uncertainties associated with the lead placement procedure, the location of the medical lead may not be the same as the region generating the maximal signal source, resulting in an offset between the target anatomy and the lead location. However, it is not necessary for leadto be offset from the target anatomy as a lead placed at the target tissue that generates the strongest signal may provide effective stimulation therapy. A clinician may choose to implant leadoffset from target tissue or directly at or within the target tissue that generates the strongest signal.

When using medical leads with larger number of electrodes, the time necessary for a review by a clinician grows. Further, the exploration and programming time required for directional stimulation across multiple combinations of electrodes increases as well. To reduce the time required of the patient and the clinician, in some examples, a representation of signal strength sensed by multiple combinations of electrodes may be displayed to the clinician. The clinician may then select, or the system may automatically select, electrodes to provide electrical stimulation based on the sensed signals (e.g., the electrodes that sensed the greatest signal strength).

In some examples, a device (e.g., IMD) includes sensing circuitry configured to sense electrical signals from a first plurality of electrode combinations, each of the first plurality of electrode combinations comprising a same reference electrode of a first lead and at least one, different sense electrode of a second lead. In some examples, the device also includes processing circuitry configured to record the sensed electrical signals from the first plurality of electrode combinations, provide representations of the recorded sensed electrical signals, receive an indication, from a clinician, of two or more selected electrodes, and control delivery of electrical stimulation via the two or more selected electrodes.

These sensed electrical signals for the particular patient from combinations of electrodesand/or electrodesmay be represented on a display or user interface (not shown in) at programmer, and/or another computing device. A clinician may select an electrode combination to provide stimulation therapy based on sensed signals from a plurality of different electrode combinations. For instance, a clinician may select an electrode combination including a combination of one or more of electrodesand an electrode on IMD(e.g., a case electrode or can electrode), a combination of one or more of electrodesand an electrode on IMD, a combination of two or more of electrodes, a combination of two or more of electrodes, or a combination of one or more of electrodesand one or more of electrodes.

IMDmay be configured to deliver electrical stimulation to the particular patient via the clinician selected electrode combination. As one example, where a clinician selects the electrode combination, the clinician may select the therapy to deliver electrical stimulation to the particular patient via the selected electrode combination. As yet another example, the clinician may input the selected electrode combination to programmersuch that programmerautomatically selects a therapy and configures IMDto deliver electrical stimulation to the particular patient via the selected electrode combination. As yet another example, the clinician may use a computing device to select an electrode combination that may be communicated to programmerthat may configure IMDto deliver electrical stimulation to the particular patient via the clinician-selected electrode combination.

is functional block diagram illustrating components of an example IMD. In the example shown in, IMDincludes processing circuitry, memory, stimulation generator, sensing circuitry, interface, telemetry module, and power source. Memory, as well as other memories described herein, may include any volatile or non-volatile media, such as a random-access memory (RAM), read only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, and the like. Memorymay store computer-readable instructions that, when executed by processing circuitry, cause IMDto perform various functions described herein.

In the example shown in, memorymay store therapy programs, operating instructions, and electrode selection algorithm, e.g., in separate memories within memoryor separate areas within memory. Each stored therapy programdefines a particular program of therapy in terms of respective values for electrical stimulation parameters, such as an electrode combination, current or voltage amplitude, and, if stimulation generatorgenerates and delivers stimulation pulses, the therapy programs may define values for a pulse width and pulse rate (i.e., frequency) of a stimulation signal. Each stored therapy programmay also be referred to as a set of stimulation parameter values. Operating instructionsguide general operation of IMDunder control of processing circuitryand may include instructions for monitoring brain signals within one or more brain regions via electrodes,and delivering electrical stimulation therapy to patient. As discussed in further detail below and in accordance with one or more techniques of this disclosure, in some examples, memorymay store electrode selection algorithm, that may include instructions that are executable by processing circuitryto select two or more electrodes to sense electrical stimulation. For instance, electrode selection algorithmmay be executable by processing circuitryto select one or more electrode combinations of electrodesand/or electrodesto sense physiological signals and/or deliver electrical stimulation in accordance with the techniques of. In some examples, electrode selection algorithmmay be executable by processing circuitryto select or suggest one or more electrode combinations of electrodesand/or electrodesto sense physiological signals and/or deliver electrical stimulation automatically based on the sensed electrical signals. In some examples, electrode selection algorithmmay be executable by processing circuitryto select one or more electrode combinations of electrodesand/or electrodesto sense physiological signals and/or deliver electrical stimulation based on input from a user, such as a clinician.

Stimulation generator, under the control of processing circuitry, generates stimulation signals for delivery to patientvia selected combinations of electrodes,. In some examples, stimulation generatorgenerates and delivers stimulation signals to one or more target regions of brain(), via a selected electrode combination from electrodes,, based on one or more stored therapy programs. In some examples, therapy programsare chosen at programmerand/or an external computer and transferred to IMDand stored in memory. The target tissue sites within brainfor stimulation signals or other types of therapy and stimulation parameter values may depend on the patient condition for which therapy systemis implemented to manage. While stimulation pulses are described, stimulation signals may be of any form, such as continuous-time signals (e.g., sine waves) or the like.

The processors described in this disclosure, including processing circuitry, may include one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry, or combinations thereof. The functions attributed to processors described herein may be provided by a hardware device and embodied as software, firmware, hardware, or any combination thereof. Processing circuitryis configured to control stimulation generatoraccording to therapy programsstored by memoryto apply particular stimulation parameter values specified by one or more programs, such as amplitude, pulse width, and pulse rate.

In the example shown in, the set of electrodesof leadA includes electrodesA-D, and the set of electrodesof leadB includes electrodesA-D. Processing circuitrymay interfaceto apply the stimulation signals generated by stimulation generatorto a selected electrode combination from electrodesand/or electrodes. In some examples, interfacemay include individual voltage or current sources and sinks coupled to each electrode (i.e., a separate voltage and/or current source and sink for each of electrodesand/or electrodes). In some examples, interfacemay include a switch module that may couple stimulation signals to selected conductors within leads, that, in turn, deliver the stimulation signals across selected electrodesand/or electrodes. In the example where interfaceincludes a switch module, the switch module may be a switch array, switch matrix, multiplexer, or any other type of switching module configured to selectively couple stimulation energy to selected electrodesand/or electrodesand to selectively sense bioelectrical brain signals with selected electrodesand/or electrodes. In some examples, a switch module may be used to couple sensing electrodes of electrodesand/orto sensing circuitry, but not to couple stimulation electrodes of electrodesand/orto stimulation generator. Hence, stimulation generatoris coupled to electrodesand/or electrodesvia interfaceand conductors within leads.

As discussed above, processing circuitrymay control interfaceto apply the stimulation signals generated by stimulation generator, or sense electrical signals by sensing circuitry, to a selected electrode combination of electrodesand/or electrodes. In some examples, the selected electrode combination may be monopolar. In other words, one or more electrodes (e.g., one or more cathodes) may be located on leadA and the other electrode (e.g., an anode) may be located on leadB. In some examples, the selected electrode combination of electrodesand/or electrodesmay be unipolar. For instance, a unipolar selected combination may include one electrode of either electrodesor electrodesin combination with an electrode on the housing of IMD(i.e., case or can), where one is an anode and the other is a cathode. In some examples, the selected electrode combination of electrodesand/or electrodesmay be bipolar. As one example, a bipolar selected combination may include two electrodes from electrodes, where one is an anode and the other is a cathode. As another example, a bipolar selected combination may include two electrodes from electrodes, where one is an anode and the other is a cathode. As another example, a bipolar selected combination may include an electrode from electrodesand an electrode from electrodes, where one is an anode and the other is a cathode. In some examples, the selected electrode combination of electrodesand/or electrodesmay be multipolar. As one example, a multipolar selected combination may include multiple anodes and/or multiple cathodes selected from electrodes. As another example, a multipolar selected combination may include multiple anodes and/or multiple cathodes selected from electrodes. As one example, a multipolar selected combination may include multiple anodes and/or multiple cathodes selected from electrodesand electrodes.